不定式起名词、形容词、副词作用,在句子中除了动名词所起的作用外,还可以作状语。
动名词起名词作用,在句中可以作主语、宾语、表语、定语、主语补足语、宾语补足语。
两者之间的差别:
1) 不定式的逻辑主语必须与句子的主语一致,而动名词的逻辑主语范围较大,它可以指主语,也可以是泛指。如:
I hate to work on weekends. (指自己干活)
I hate working on weekends. (可以指自己,也可以泛指)
2) 动名词多指抽象的、概念性的动作,可以是多次的、经常的行为,不定式多表示具体的动作,尤其是某一次的动作。如:
Reading in bed is a pleasure.
I like swimming but I don’t like to swim in the pool today.
3) 在某些动词之后只能用动名词,而另外一些只能用不定式
后接不定式的动词有:afford, agree, aim, ask, claim, choose, decide, decline, demand, desire, determine, expect, fail, hope, manage, offer, plan, pretend, promise, refuse, resolve, threaten, wish等。
后接动名词的动词有:admit, avoid, consider, defer, delay, dislike, enjoy, escape, fancy, finish, imagine, include, keep, mind, miss, postpone, practice, recall, recollect, resent, resist, risk, stop, suggest等;短语有have done, give up等。
4) 既可以接不定式又可接动名词。常见的有:begin, continue, dread, fear, forget, hate, help, intend, learn, like, love, need, neglect, proceed, propose, regret, remember, start, try, want等。
以上动词接不定式与动名词一般没有多大区别,但有时却有很大区别,主要表现在以下:
① remember和forget后接不定式时,表示没有发生的动作,而接动名词时表示已经发生的动作。如:Did you remember to lock the door?
I remember seeing her before.
I forget to buy the book.
Shall you ever forget hearing her sing?
② stop, try, mean, help, regret则是另外一些
其中regret后接不定式表示将来的动作;后接动名词表示过去或现在的动作;接动名词的完成式表示过去的动作。
如:I regret missing the film.
I regret to say that I cannot come.
5) 有些动名词表示被动意义,而不定式则用其被动式表示被动意义。如:
It needs to be repaired.
It needs repairing.
6) should(would)like, love等之后用不定式。如:
I’d like to thank you.
I’d love to come sometime.